| 摘要 |
PURPOSE:To always set magnetic field strength equally extending over the recording area of a medium plane by detecting the position of an optical head existing on the medium at present, and supplying a current corresponding to the position to a bias magnetic field coil. CONSTITUTION:An optical disk device is provided with an electromagnet 1 which becomes the bias magnetic field coil to cover the recording area in a diameter direction of a disk 7 with a magneto-optical head. Furthermore, it is equipped with the position detector 3 of the head 2, a position signal output part 6, a memory 5 in which a prescribed current corresponding to the position to uniformize a bias magnetic field receiving the output of the part 6 is stored in advance, and a driving circuit 4 to permit the current to flow on the electromagnet 1 by the output of the memory. In such a way, in recording and erasure, the same bias magnetic field can always be obtained in spite of the position of the head 2 only by inverting polarity, and a characteristic can be improved, and also, it is not always required to permit a large current to flow by aligning to a low magnetic field position, and power consumption can be reduced. |
